Cogito Ergo Sum
by Luna Bass
Summary: Sayu's world is a lonely one - the only person she knows to be like her is her brother, and he is trapped in a kind of thinking that she can neither relate to nor pull him out of. Until one day, when she meets someone whose perspective is the same as hers, and something strange, beautiful and new blossoms into being.
1. Chapter 1

One day, her older brother came home from a long day of school, and Yagami Sayu knew something was different.

She watched him make his way up the stairs, technically present but his mind elsewhere. At the time, Sayu had thought very little of it, and had gone back to playing video games. Light was intense, and took himself very seriously. No doubt his future was on his mind.

A few days later, he was still different, but something had further changed. He seemed more confident, in control, less preoccupied – at the same time, thinner, and slightly ill. Sayu carefully watched him, when she was sure he wasn't paying her any attention (not that he normally did, unless she made sure of it), and she eventually arrived at the conclusion that this wasn't about school, as most things in Light's life were.

Light was the oldest child, the one always at a stage that his parents were unsure about. And so they put a great deal of pressure on him to be intelligent and perform perfectly, which he did. Thus, they were assured they were raising him right.

Sayu was the youngest child, the one going through the stages that Light had already passed through – they knew what to do with her, and they felt relaxed enough to give her freer reign than they had given Light. Sayu flourished and ran wild where Light had been rigidly contained, pruned and cut into a specific mold, for fear of letting him take the wrong shape.

Sayu had always thought it was very silly of them to think that all geniuses would act and present themselves like Light – they were all so different in personality, after all, and there was such variety in the world, in their upbringings, that they surely would all be different. She didn't want to go so far as to say that she was proof of that, but she wouldn't be surprised if that turned out to be a correct assumption.

She didn't care about school, not like Light had to – she got good enough grades to make sure she didn't get in trouble, but it really wasn't the most important thing in life. Light had been taught to value all the things his parents did, which were societal concepts, like justice, academics, prestige and honor. At the age in which Light was being praised for his genius openly in class, rigorously made to memorize and challenge and prove himself constantly, Sayu was allowed to run off and play, stagger through the park, get bored playing with other children, and find her way to the library to read Nietzsche, Kant, Suzuki, Lovecraft, Poe, textbooks about quantum physics and philosophy, treatises on religion, and instructions on how identify the components of stars from the colors in their light.

Why, when the universe was so big and so incomprehensible, would she give a damn about her own intelligence relative to that of billions of other, equally tiny humans? Life was short, after all – too short to worry about petty little things like politics or crime or academic success. Flowers were blooming, the sun was shining, and who knew if any of them would be around to enjoy these things tomorrow, so why not enjoy them today?

If her parents knew how smart she really was, they would try to turn her into Light – and Light, whether he himself knew it or not, was miserable. And so she carefully kept it a secret, hidden and locked away from the rest of the world, even though she wanted to scream the truth from the rooftops and tell them all that it was pointless to keep living their lives this way.

Thus, when this development came to her attention, Sayu realized that Light must have found something more worth his time than school and pleasing their parents. She resolved that whatever it was, she would find out. Her brother had found a reason for existing that he wasn't telling Mom and Dad about, and she wanted to know what. Maybe, finally, she would be able to share her thoughts with him – lift him above the inanity, the human structures that they had drilled into his mind, and together they would soar in the stratosphere, discussing concepts like destiny and kindness like the intangible things they were.

Sayu was a happy person, but it was lonely in her world full of poetry, bright colors and strange, wonderful ideas. If she could share the space in her mind with someone, _anyone_ , that would be the day she knew herself to be truly happy.

So one day, while Light was out, she searched his room. Sayu knew all about his many safeguards – from the pencil lead to the door handle, she carefully bypassed them all, down to the last millimeter. He would never know she was there.

She discovered the false bottom to his drawer when she saw the pinhole on the underside (she'd taken them out of the desk, looking for carefully-hidden documents pinned to the back of the drawer – she had several hidden in her own room, written in code and carefully concealed in the same way). Guessing at what the pinhole was for, she compared several items on his desk to the hole's size, until she realized that it was just the right size for an unscrewed ink cartridge. When she decided she had found the right pen, Sayu used it to lift the false bottom.

The first thing she noticed was not the script on the front of the book (her English being rusty), but the mechanism he used to hide and protect it. The wires, the bag of gasoline... She hesitated before taking it out. Light was willing to risk both his own and his family's lives to keep this secret. Whatever this was, he thought it was more important than anything else. _What are you up to, big brother?_

Sayu rolled up her sleeve, copied the words on the front cover and the following pages onto her arm with a marker, and then opened the rest of the notebook.

Inside, thankfully, was Japanese. There was a long list of names – none Sayu recognized. The next six after the first one seemed to be variations on the same name, and all had the words 'car accident' after them. The rest were alone. After the third new name, the writing became quicker, more close together, as if Light had become more sure of what he was writing down. Sayu took note of as many details as she could, noting especially the name furiously scrawled across one page in English. It was odd, she felt like she'd seen it before...

And then she shut the notebook, and put it away exactly as Light had left it. His bedroom looked untouched when she closed the door (leaving the door handle in precisely the position Light always did, replacing the paper and the pencil lead), her mother was busy in her home office, and her long sleeve hid the notes she had taken.

Sayu wouldn't tell her parents about the gasoline – indeed, she planned from the beginning not to tell them anything about what she found. She came from a family that kept secrets from each other, whether the rest knew of that or not, and she could keep hers better than anyone.

Besides, it didn't really matter. Nothing really mattered, unless Sayu chose to assign meaning to it. That was the beautiful thing about her philosophy – it didn't obligate her to care.

Late that night, computer muted and translation software on the screen, Sayu decoded the English words in the book.

 _Death Note_

 _The human whose name is written in this note shall die._

Sayu might have thought Light had made the book himself, in English to keep their parents from reading it – he was a very resentful person, after all – but for the fact that it was on black paper, with white ink, and not in Light's handwriting. _Written_ , somehow, on black paper, with white ink. A chilling thought by itself. And even if he had made the book, and it was really nothing more than something to exercise frustration on, why did he hide it such a risky manner?

 _This not will not take effect unless the writer has the person's face in their mind when writing his/her name. Therefore, people sharing the same name will not be affected._

 _If the cause of death is written within 40 seconds of writing the person's name, it will happen._

What if someone wrote the name, and then, within 40 seconds, someone else wrote the cause of death? Would that count? And what if the cause of death was written first? Sayu knew Light hadn't made this – there were too many loopholes; if he'd come up with the rules, he would've made them clearer. So whose invention was this? Someone on the internet? Was this a trend going on that Sayu was unaware of?

 _If the cause of death is not specified, the person will simply die of a heart attack._

Well that was a silly default to have. Not everyone was in danger of heart attacks – most people who had heart attacks already had weak hearts. Wouldn't it be simpler if they just died of the nearest potential accident? Those were far more common than heart attacks – and less suspicious, if the subject was healthy. This had to be a joke notebook going around – whoever had made it hadn't had the slightest idea what they were doing.

And yet – Light had hidden it in such a dangerous way... What could explain that?

 _After writing the cause of death, details of the death should be written in the next 6 minutes and 40 seconds._

There was something she was missing here, Sayu was sure of it. But she took a wet towel and washed off her notes, deleted the translation, and went to bed. She would sleep on it – tomorrow, she might remember what it was.

 _Kira._ Of course.

At lunch, one of her friends had doodled Lind L. Tailor's name in their notebook, in English and Katakana. Sayu had only heard the name on television while she was in another room, just before Kira killed him – she had rushed in to see what was happening, and the screen had already cut to L's real announcement.

Sayu had hoped that Light had found something, a hobby that would truly challenge and delight his intellect, distract him from the ills of society that plagued him and their father. But no, he had found something much worse, something that would only take his false idea of justice and twist it to hurt himself and others. This could have been an intriguing mystery, something to investigate with science, an experiment Sayu would have been all too happy to participate in, but Light (Kira) only seemed interested in _using_ it. It was no wonder that her brother had begun to look sick.

When she went home that day, and saw a tall, dark, frightening figure floating behind her brother, her heart almost stopped, then started beating like her life was in danger.

Sayu had quickly looked away, but made it look casual, like she was looking down to kick off her shoes. Light was acting normal – she better act normal too. Whatever it was, it might not want anyone to see it. Knowing what Light had in his desk, it might well be the Grim Reaper or something, and Sayu had no desire to risk incurring the wrath of a supernatural being.

(She did, of course, consider that she might be hallucinating. But such things either tended to run in families, or be triggered by something else, like immediate trauma or hallucinogens. The former was untrue in her case, and the latter seemed highly unlikely. Besides, this was too coincidental, after having just discovered Light's secret – and Sayu wasn't such a rigid thinker as to deny the possible existence of such beings.)

The real question was, how could she see it? Sayu observed it carefully in her peripheral vision, always making sure to be focusing on something else as she and Light set the table.

It had enormous feathered wings, but it didn't seem to be using them much, only making the apparently minimal effort it took for it to float. Its face was almost human-like, but its expression was perfectly blank as it surveyed the room, scratching its side. If it were human, Sayu would have interpreted its body language as bored.

At some point as they were eating (while Sayu kept stealing glances at the monster), it began to chuckle.

She hadn't even recognized it as laughter at first – it had taken every ounce of her self-control to keep from screaming when she heard it. Out of the corner of her eye, she saw Light jump very, very slightly. So he could see it too.

"Funny," it said, its voice like the wind lifting dust across a field. And then it became quiet again.

Light was tense for the rest of the meal. Sayu could practically feel his mind racing, trying to analyze what it meant by that. How much did he know about the creature? If it could speak, did it speak to him? How long had he been seeing it? When had it come to him, started following him?

Was Light in danger?

It wasn't long before she saw it again.

Sayu was completing her homework before bed (she preferred to rest after school, relax with books, manga and other distractions, then do her homework at night. It took minimal effort to get average grades, and she knew how to cover up the bags under her eyes). Only her desk lamp was on, and her room was dark.

It was hard to focus, knowing the creature might still be in the house. Was it with Light? How could he sleep if it was? Was he asleep? Did the creature sleep? What _was_ it?

"Hi," said a voice above her head.

Sayu stifled a screech – and looked up.


	2. Chapter 2

Above her, there was a pale, inhuman face, sticking out of the ceiling. Its smile was full of terribly sharp teeth. Sayu swallowed, willing her pulse to calm itself. "Hello."

The face began to lower itself from the ceiling, a neck, shoulders and wings following. Sayu stood up out of her chair and backed up a ways as the creature descended and finally crossed its legs, floating upside-down and looking at her with eerie yellow eyes.

"You can see me. You shouldn't be able to see me." Its voice is deep, and alien – there are no layers to it, like they do in the movies to make it sound strange, but its more chilling than anything Sayu could have imagined. "You must know about the Death Note, then?"

Sayu could only nod, her voice caught somewhere in her throat. The creature continued, its tone turning curious – an oddly human touch. "How? Your brother took a lot of precautions to keep it hidden. Even I was impressed. Are you a family of geniuses?"

Sayu managed to find her voice again, though barely. "Something like that." There was a pause, and they carefully studied one another. Her eyes glanced over his jewelry, the clothes sewn into his skin – was it all real, she wondered, or an illusion to cover up something malevolent and incomprehensible?

He (for it was easier for Sayu to think of this being as a he) broke the silence. "What are you going to do, now that you know Light is Kira?" The creature's eyes flashed scarlet as he leaned forward, unnervingly focused; Sayu could see herself reflected in his pupils.

"Nothing," she said, her voice much calmer than she felt. "I'm sad Light thinks he has an obligation to kill people, but otherwise I don't care." And wasn't that strangely freeing, to say that? That she cared about her brother's mental health, and other people's lives meant nothing to her? The human right to life was just a social construct, after all, the only real consequences murder had being the grief of loved ones and the guilt of the person who committed the so-called crime. It took a toll on the soul, if such a thing existed, and Sayu ddin't want that for Light.

The creature was silent as he slowly turned himself upright to look at her properly. " _Interesting_ ," he said. Sayu hoped that was a good thing.

"I suppose Light was right, about humans hiding their real selves from each other." The creature cocked his head to the side. "My name is Ryuk."

"You are, ah, **Mister** Ryuk?" Sayu asked, recalling a little of what she had learned about gendered English honorifics.

"I suppose. I don't have a family name – I'm just, well, Ryuk."

"It is...interesting, to meet you, Ryuk-san." Sayu couldn't bring herself to honestly say it was a pleasure. "May I ask why you're following my brother?"

"Oh." He tilted his head. "Well, I have to now. You see, the Death Note was once mine, until I sent it to the human realm. Now it is his, because he was the one to pick it up. I must follow him until the day he dies."

Seeing Sayu's expression, Ryuk seemed to realize this wasn't a helpful explanation. "I'm a shinigami," he added, equally unhelpfully.

Sayu sighed and sat back down. He didn't seem to be an imminent threat for now, thought it would probably be unwise to discount all danger. "Is there maybe a beginning you could start from? What a shinigami is, what a Death Note is, where you come from?"

In the end, the full story that he gave her wasn't much in the way a real explanation. After he left (which was after she wrung a promise to return and talk to her later out of him), Sayu was left in bed, staring up at the ceiling, mind racing and fully in the knowledge that she would be getting no sleep whatsoever that night./

Were shinigami an alien race? Were the Death Notes advanced technology or just magic? _How did they work?_ How long had the shinigami been living parasitically off the human race? There were too many questions which bore looking into – she had to dig out a notebook and write them all down as they came to her (in code, as it always was with things she couldn't afford her parents knowing about) and by the time she stopped to rest, her hand ached.

Too many questions, most of them about this supernatural occurrence – but as well, she still worried about Light. Should she stop him? Out of duty to her brother, if not to society? He would end up going to Mu no matter what she did, and it might end up being against his will, and Sayu's complicated and atypical sense of morality only complicated matters. She almost envied Light for his simplified view of ethics – to him, it really was that easy to make a decision.

She would never personally kill someone, unless they were threatening the safety or happiness of her or someone she loved. The potential for self-torture was too great. It might be easy for Light, she supposed, considering he didn't seem to view the people he was killing as innocent, but did it really matter if they were or not? They were as human as he was, as anyone they knew or went to school with. Would he kill his own family if they committed murder?

Too much, too many thoughts flying through her head, too late at night to be dealing with them; more than ever, Sayu wished she had someone she could talk to about all these ideas, someone closer than just a friend, someone at her level of intellectual and emotional distance from others, someone to reflect her view of the universe off of to see if any of it made sense. She wondered if Light ever felt this kind of loneliness, or if he was satisfied, even proud of the fact that he was so unique. As arrogant as that perception sounded, she almost hoped the latter were the case. The former was so crushing and dreadful she could hardly stand it at times.

Sayu, having just confirmed that there was an afterlife, wondered if maybe she could just wash her hands of these earthly concerns once and for all. What were the qualifications for getting into Heaven? Somehow, she doubted Ryuk knew, and Sayu suspected she might not even meet them. Besides, there were just too many questions... God, why her? Why Light?

She turned over and shut off her nightlight, trying and failing to banish her thoughts and get to sleep. Things always seemed better in the morning, but that was only the case if she was rested.


	3. Chapter 3

It was the weekend. Sayu was reading a fluffy manga in hopes of clearing her head, and Ryuk came floating down through the ceiling.

She had gradually grown more accustomed to his presence (though his floating through walls was still unnerving), and had taken to asking him questions whenever they were alone. The shinigami of his world seemed very oblivious and self-centered, and Sayu couldn't blame him for wanting to leave, even if he brought the chaos of the Death Note with him.

His relationship to Light disturbed her somewhat, though Sayu supposed that she didn't have much ground to stand on, considering she only heard Ryuk's side of things. Try as she might, she couldn't bring herself to talk to Light about what he was doing. (Was it because she was afraid for herself? Afraid of what he was becoming? Or of what she might find out about her brother, of the decisions he had made for himself?) Everything he did now seemed suspicious, and made her question his reasons behind it, making her itch with paranoia.

These conflicting and disturbing thoughts whirling through her mind, making her wary as always, she opened her mouth to say hello.

"Don't talk," Ryuk warned. "L's set up cameras and wiretaps in the house."

She smoothly turned her greeting into a yawn, desperately trying to suppress her alarm as her pulse quickened. So the NPA had stooped to breaking the law – and Light had made some kind of terrible error that made him a suspect. Raw fear coursed through her, and if she hadn't been resting her arms on the floor, her hands would have been shaking.

Her big brother was in way over his head, and for all their wiles, this wasn't something she could ever protect him from or help him with, even if he believed her when she revealed herself. In all her life, as short as that life was so far, Sayu had never felt this helpless.

"They don't seem to think you're a suspect," Ryuk continued. Well of course they didn't – they had no reason to. Light was the only one who, very publicly, might have a motive. _God, big brother, for someone so smart, how could you be so stupid?!_ "And Light doesn't even think you know anything." This he cackled at. "You sure have them all thoroughly fooled." His tone turned curious. "Why do you hide it from them, anyway? Your intellect, I mean."

Sayu yawned again, extra wide and extra loudly, to remind Ryuk of the wiretaps. "Oh, right." She closed her manga and pulled out her sketchpad as an idea occurred to her. Maybe they could hold a conversation anyway.

She started with drawing a brain. Ryuk, seeming to get the idea, peered over her shoulder as she drew. Around it, she started drawing a cage made of objects. "Pencils, workbooks, textbooks, rulers – school, maybe? Is school a prison?" Looking down at her sketch, Sayu nodded as if pleased with it. "That doesn't explain why you hide." Shaking her head, as if realizing something was missing, she added a glowing lightbulb over the cage. "Wait – for Light? School is a cage for Light!" Ryuk clapped his hands like a child. "Heh, this is almost like a game!"

Sayu smiled in spite of herself, and made a mental note to introduce Ryuk to more things in the human world, both for her own amusement and to gain more knowledge about shinigami in general. She flipped a new page over the old one, and traced over the brain, adding a little bow on top to make it clearer. "You?" She made the tools for her cage scant and few, scattered around her and overcome with weeds whose roots traced back to her brain. There were hands trying put the cage together, but the weeds struggled against it. "You're stronger?" Sayu shook her head, as if dissatisfied. The weeds were her personality – the thing that prevented them from seeing her the same way they saw Light, from trying to restrain her.

Ryuk tilted his head. "You saw what was happening to him – so you fought back? You escaped by playing dumb."

Her eyes slid up to look at his face – she almost let her guard down, but Sayu kept her face carefully blank. She had never thought of it that way before. It was true that she had always known her parents would have put the same pressure and struggles on her if they had been given the chance, but she'd been assuming it had more to do with being the younger child. Perhaps she had, on some level, seen Light's unhappiness, and unconsciously hid herself. It seemed like a strange idea, but people all over the world developed similar defense mechanisms all the time, without even knowing it was happening. Children were especially susceptible.

This immortal alien had somehow seen the bigger picture, the entirety of what she and Light were only able to catch glimpses of - the trap of performance, in its many forms, snaring them both in its grasp and binding them to this mundane sphere.

Ryuk's crimson eyes glinted in the dimming light of the late afternoon. "You thought it was just because they had different expectations for you, didn't you?"

Even if she had had the freedom to speak, Sayu could not have brought herself to. She realized that instinctively, she had always tried to look away from Ryuk even as she tried to get to know him, as if he were something to be avoided, something no mortal should be seeing – which, in a way, was correct.

But now, she was seeing him – really seeing him, in a way she suspected Light would never even think to. This alien, knowing being, as different from a human as anything she knew, yet with just as many layers and as much complexity as any self-aware person, stood before her and he _observed_. He observed in a way that never came naturally to Sayu, never came naturally to any human animal, but that she always aspired to mimic.

A strange wonder overcame her, a feeling she couldn't name. She felt as though she should be floating, just like Ryuk was now. Or at least be singing a Disney song (not that any Disney song could fully capture what she was feeling right now).

Sayu nodded, careful to make it seem as if she were just deep in thought. Ryuk had a new expression on his face, as much as his face could have recognizable expressions. He leaned back, hands folded in front of his knees. "You humans are very interesting." _So are shinigami_ , thought Sayu.

Later, when she was in her room, she drew up a plan for working around the cameras. First on the list was dealing with the pictures she had drawn for her conversation with Ryuk, as those could raise questions if discovered. Sayu considered destroying them, or scribbling over them and throwing them out, but that would only raise more questions.

She certainly couldn't hide them the way she did her journals, or even access those places in any way, as that would reveal that she was keeping secrets. And so she slipped them into her school binder, between her worksheets and her chibi doodles, and resolved to shred them while she was at school.

Next was deciding how to handle undressing and bathing. If her father was still on the task force performing this spying, then he would certainly protest this invasion of their privacy, Sayu knew him well enough to be sure of that. He would try to confine the viewing of private moments like these to himself and one or two others who he trusted, and as mired as he was in the concept of duty, Sayu did trust him in that regard at least. Being naked in front of her father would be embarrassing enough, but hopefully he would minimize the possibility of strangers seeing her. There was no way of avoiding the cameras without becoming suspicious.

Sayu tried to comfort herself with the thought that he had changed her diapers as a baby, and would probably be just as embarrassed and uncomfortable about this as she was. It didn't help much.

Would he notice, if she took shorter showers? Probably not, he was never at home when she'd taken them before. Mom might, but she wouldn't comment on it. The one she worried most about noticing such a convenient change was Light, as not much slipped past him.

The most effective thing to do, she concluded, was to change her shower schedule a day later. That way, Light wouldn't notice as much, and if he did conclude that she had found out about the cameras, at least he wouldn't suspect her of finding out from Ryuk. Changing her schedule at all was risky, but being fourteen and self-conscious, she considered it worth it.

The very next morning, while laying around watching her shows, Sayu learned that shingami could get addicted...to apples, apparently.

"Light made me search for all the cameras," Ryuk griped, twitching and squirming. "I can't eat apples in the house without it showing up on camera and looking weird." She gathered that he wouldn't want it looking weird because it would give away the game too quickly, and Ryuk would be bored again. "I'm screwed until they pull them all out of here."

Sayu took out her red and green pencils, and drew an apple with a question mark for a stem. "Why apples?" She drew a sun in the background – their agreed-upon symbol for a yes, as she couldn't keep nodding and shaking her head for no reason. "Well," Ryuk seemed to struggle to articulate himself, making gestures, scratching his neck and looking back and forth. "They're – they're juicy. They crunch. They're so full of flavor. They smell nice. There's no food in the shinigami world worth having; apples are like the opposite of anything I've tasted there. Everything there is rotten, or already dirt."

A world of death indeed. Sayu sketched a black skull in the middle of the apple. "Huh. I hadn't thought of it like that, but yeah. Everything is dead there."

Sayu could hardly wait until she could talk to him properly. Ever since their first conversation with the drawings, she had felt an urge to connect with him, show him things about his world that he hadn't known, even as he showed her things about her world that she hadn't known. Perhaps all they had ever needed was an outside perspective – she for her loneliness, he for his boredom.

Except – except she suspected that his boredom might be ennui, just another kind of loneliness. Perhaps an ennui no human could understand, and no shinigami either, if what he told her of his world was true. But this idea had sparked a fire in her, a desperation that drove her to tears the night before. Sayu was so _tired_ , tired of floating along alone. Now she had met a being who (she was fairly certain) saw things the way she did, and she wanted nothing more than to reach out. She had never wanted anything so much in her life.

"It's like liquor, I suppose, at least that's how I explained it to Light. I think its probably a lot more psychological than physical though." Everyone else was out of the house, thank goodness, and her brother had asked to be alone in his room, so Light wasn't at risk of interrupting and wondering why Ryuk was talking to his sister. That, above all else, was something Sayu wanted to avoid explaining. She was comfortable with their relationship as it was now, and it didn't need to change. "My mouth feels so dry, and I keep twisting up into a pretzel. This is the worst," he lamented. She doubted he was serious, considering the punishments Ryuk had told her about for various crimes shinigami could commit. Still, Sayu sympathized.

Almost without thinking (she'd had a lot of practice sketching lately) she found herself drawing a girl with a bag of apples on a bench, holding up one that was half-eaten. Ryuk shook his head. "Can't. I have to stick close to Light as long as he has the Note – going out to get apples without him would be straying too far. Thanks for the thought, though."

Sayu smiled to herself (Hideki Ryuga was on, it wouldn't look too weird) as Ryuk floated away. She felt confident that they would remove the cameras soon – they had too many to have around and not risk being discovered for long. She'd already had to pretend not to see a few, and suspected Light of doing the same.

After an ordeal like this, a real conversation – maybe over some apples – would be extraordinarily refreshing.


	4. Chapter 4

During dinner that night, Light made a dangerous, awful, arrogant, selfish mistake.

A news bulletin came on while they were listening to music, announcing that Interpol was sending fifteen-hundred agents to Japan to aid in the Kira case. Considering Light was mainly attacking in Japan, Sayu doubted Interpol would actually consider it such a high priority. A crack team, out of obligation, perhaps, but fifteen-hundred? She would have put a little asterisk next to the word 'agents.'

But then Light couldn't just say nothing about it and maintain a low profile, nooooooo, he just _had_ to make a remark.

"Interpol is so stupid."

Sayu couldn't help it. "What?" she blurted out in her disbelief. _You know about the cameras, idiot! Now is not the time to show off!_

Her brother shrugged. "What's the point if they announce it like this? If they're going to send in all those detectives, they should just keep quiet about it and let them work in secret." _Shut up, Light, shut up shut up shut up! You're going to get yourself arrested!_

Her silent pleas did nothing, and Light continued to dig his own grave. "Those FBI agents were here on a top-secret mission, and look what still happened to them!" Aaaaaand he was drawing attention to his own handiwork. It was like the smug bastard had a death wish! "If Kira knows about these guys, he's going to get them, too, for sure."

All Sayu wanted to do was shake him, pound her fists against his chest and scream _Whatareyoudoingstopitstopitnow_ but instead, she kept a tight grip on herself and her impulses, and used all her willpower and strength to give the vapid, inane response that was, as always, expected of her: "Oh, yeah, you're right! Smart as ever, Light."

(Oh, how dearly she wished Ryuk were here. He might've understood how hard it was for her to say that with a straight face, even if his laughter tipped Light off.)

But Light wasn't finished. "That's why I bet it isn't even true. This is just a ruse to put pressure on Kira."

Oh, how Sayu wished he had stopped there (stopped earlier, even). But he had to put another nail in his coffin.

"But, it's pretty obvious," he said _with a goddamn smirk_ , "so I bet Kira's figured that out, too."

 _Are. You. SERIOUS?!_

Calling _that_ move obvious, when here he was, practically jumping around in his underpants with red paint and a target on his forehead, shouting 'I'm Kira, I'm Kira!'?! The audacity! The idiocy! If he weren't her brother, and making a horrendously terrible mistake by all but daring L to put him on the top of his suspect list, Sayu just _might_ have admired how ballsy he would have to be to say that, knowing he was being listened to.

When Light was done eating and incriminating himself, and he grabbed a bag of potato chips to take up to his room, Sayu made a dig at him getting fat, and it deeply frustrated her that it was the closest she could get to beating the shit out of him for being such a moronic, thoughtless, cocky, selfish, arrogant _dick_.

Ryuk came to visit her in her room a few days later, while she was listening to music. She casually slung the headphones around her neck and slid her sketchpad towards her.

"The cameras are gone, but Light still thinks there might be wires." Sayu noticed he had an armful of apples, and he was munching on them as he sat down on the edge of the bed next to her. "I have a question."

Seeing as there were no cameras to watch her now, and she could dispose of the notes the same way she disposed of the pictures, Sayu wrote down her answers. _Ask away._

"I know what Light does, with his smarts," Wasting them, presumably. (Sayu was still mad about the news bulletin.) "but what do you do? There has to be something – you act like you're average, but you must have some kind of outlet, or you'd probably waste away from boredom."

 _I read philosophy, mostly. Keep up to date with science. Conduct experiments and write anonymous papers when my family can't see. These days? Wondering about shinigami and the Death Note._

"Like what?"

 _There's enough holes in the Death Note's rules to drive a barge through. Are there other rules that aren't written down?_

Ryuk shrugged. "Probably? I wrote down all the ones I could remember, but I could have forgotten some."

So not all the Notes had the rules written down – Ryuk had done that for whoever was going to use his. _How old are you? How long have you been using the Note?What's the earliest thing you can remember? Earliest period in human history?_

Ryuk scratched his head in surprise. "You know, Light never even thought to ask me that. He's got a pretty one-track mind, that guy. Uh, I don't know, I also don't know, and the earliest thing I can remember is using the note on some old guy hunting with a spear. I don't remember when that was, sorry – shinigami mostly don't keep track of stuff like that. The first time I really remember us paying attention was during World War One or Two, I think. Some shinigami were panicking, because there were humans dying too fast for us to harvest lifespan. They thought you guys might go extinct."

 _So you only depend on humans for your life? There aren't any other species? Can you use your Death Notes on each other?_

"Yes, no, and no. Shinigami can't kill each other, only the Death King can do that."

 _Who is the Death King? What happens if a shinigami runs out of lifespan? Are there beings other than humans and shingami?_

"You sure have a lot of questions. Why haven't you asked any of this before?"

That sounded like a deflection to Sayu. _I've kind of been digesting the fact that Heaven and Hell are real. Also, well, Kira._ She had to try not to write anything too incriminating of Light, just in case. _Are there any other beings?_

"Erm," Ryuk squirmed. Sayu suspected he was often embarrassed by his own ignorance, no doubt the result of a culture that dismissed curiosity and intellectual engagement. "Well, I don't know – if there are, they aren't really our bag. The only two worlds I know of are ours and yours. There might be a few of the others who know, but if they do, they don't tell anyone."

 _And the Death King?_

"He's uh, well," Ryuk scratched his head. "I'm honestly not sure how to describe him. He's the one who basically rules us – we go to him for disputes, he gives us our Death Notes, he punishes us when we go against the laws. He's been there for as long as I can remember. No one ever explained to me why he's in charge, and I never really thought to ask."

 _Does he have a real name? Do you know where he gets the Death Notes?_

"I don't think so. I think he's the one who makes them – I can't think of where else he would get them. Some of the others think he created our world, too."

Every answer brought more questions, but she focused on the ones that had been driving her crazy. _Do you think your world might've been different at some point? More alive?_

This left Ryuk silent for a few moments.

"I..." he began hesitantly. "I don't think so, somehow. But, it's kind of strange, isn't it? A dead world. You'd think a world that's dead would've been alive at some point. Somehow I don't think it ever was, though. Less like it was alive, and then it died, and more like it didn't exist, and then somehow it did. Like time doesn't touch it."

He was silent, and completely still for some time after this. She supposed he must be thinking, but Sayu felt chills, seeing him so unmoving like this. Nothing alive on Earth could sit that still, not even plants. For a solid few seconds, Ryuk seemed to be a fixed point in space, immovable and untouchable.

Just like the world he came from.

"I suppose," he said softly, breaking his long silence, "that's why I find your world so fun to watch. Things change so fast here. Everything moves and flows from one moment to the next, so fast. It breathes like it's a living thing itself. Compared to a still, lifeless husk like home – like me," Ryuk held his palms out and spread his spindly fingers to indicate everything around them, "It's – it's like comparing existence and nonexistence. Apples and, uh, dust."

She was caught on those words, 'like me,' on him likening himself to the world he came from, and before she could process it Sayu found herself speaking. "But -" she caught herself just in time. Shocked at her own lack of caution, she clapped a hand over her own mouth as she hastily started scribbling onto the paper. Ryuk looked surprised too, though as always there was always some other, unidentifiable emotion lingering behind his eyes.

 _But you're not lifeless! You_ _chose_ _to come here! You_ _chose_ _not to lay about doing nothing! You_ _chose_ _curiosity over complacency! You're not dead, none of you are. Any one of you could come over to this world if they chose, all shinigami have it in their power to defy the Death King. The problem is that not enough of you think to choose something different to what already you know. Humans and shinigami face the same problem – we're too comfortable with the familiar and too afraid of the unknown._

Ryuk stared at the paper, and then stared at her, leaning in so close that Sayu was suddenly very aware of the details of his presence – his big, big birdlike eyes, his sharp, predatory maw, how he didn't breathe or give off heat, how his feathers made his shoulders seem wider than they really were, how his earrings only seemed to obey gravity when he wanted them to –

"You're fascinating," he murmured, bringing up a spindly black finger (God, how his claws looked so long and sharp and _dangerous_ ) and tapping the top of her forehead. "So many wonderful secrets and keen observations hidden away up in that little head of yours, and nobody has any idea. How has no one ever wondered if there's more than what you tell them you are? More than what you show them?"

As she stared up at him, his enormous hand dwarfing her supposedly keen little head, Sayu desperately wanted to whisper: _You're the one who's fascinating._


	5. Chapter 5

Light's first few days as a university student were apparently far more eventful than he let on.

Ryuk had confirmed there were no audio bugs, which came as a relief to Sayu, but according to an excited and invested shinigami, L was closer on Light's tail than ever before. The detective had come to To-Oh himself, under the name Hideki Ryuga (which Sayu found grossly insulting to the star himself) and was trying to provoke Light into making a mistake.

"I'll bet my entire Sailor Moon collection that he won't last a day," Sayu stated grimly as she tossed Ryuk a Golden Delicious apple out of her bag. She wondered if this made her an enabler, but there didn't seem to be any bad side effects to the apples themselves. "Light loves to brag, he can't help himself. It's like a compulsion."

"I dunno," Ryuk said thoughtfully as he bit the apple in half, swallowing a massive amount in one gulp. "He seems pretty good at keeping his cool so far. Maybe he's learned something?"

"Maybe, but he's attracted the full, personal attention of _L._ Light's an attention whore and a narcissist, he'd probably be giggling with glee well before now if he didn't think it was beneath him. It's more than just him making mistakes in covering his tracks, he _wants_ people to follow his trail of breadcrumbs so he can feel clever and admired. If he really didn't want to be caught, he wouldn't have created this whole persona in the first place."

"Yeah, I kinda got that impression from him already," Ryuk commented, slurping the juice from the exposed side of the apple with his tongue. Sayu mentally measured it until he pulled it back in his mouth with the apple. _As wide as my hand, and nearly fifteen centimeters long, at least. It should barely fit in his head, assuming it doesn't purposefully defy physics somehow._ "He's gonna be bored if he wins. Whether he knows it or not, he'd probably have more fun trying to play mind games with L while incarcerated than he would in a world where Kira reigns supreme."

Bile rose in Sayu's throat. "That's if they let him live."

Ryuk was lost in his own thoughts, ignoring the complicated feelings she clearly had about this. "Either way, I'm going to be the one that eventually kills him, but I'd rather he doesn't prolong it in such a way that it gets stale. I sure hope he doesn't end up going in a boring direction; if the game ends so early I'll be -"

"Leave."

Sayu wasn't sure what part of what he'd said had loosened her tongue, but she was clutching her covers in her hands, her knuckles white, tears gathering hot behind her eyes, her throat dry and her stomach churning.

Ryuk looked down at her in surprise, eyes glinting from red to a surprised, owlish yellow. "What?"

"Just go. I don't want to talk to you right now." Her hands were trembling as she stared up at him, trying to hold back the crying fit that was sure to come. "Maybe not for another few days."

Sayu couldn't tell what he was thinking from his face, seemingly blank as it always was, but he silently obeyed, retreating awkwardly upward to the ceiling, and he floated away just like a balloon.

With him gone, she buried her face in a nearby pillow and let the tears flow. She was careful to keep her sobs quiet as she clutched it to her, until she had no more crying left in her.

Sayu turned back over, laying on her side, staring out the window at the sunset turning the sky a bloody red. Too readily, she could see the inevitability of her brother's death playing out before her mind's eye. All it would take would be a few, swift strokes of a bone-white pen held in slender black fingers, and Light would vanish.

She'd already known Ryuk wasn't human, couldn't understand some fundamental human ideas, like familial attachment or the fear of death, but it was startling to receive a reminder of it this way. A reminder that for all that she liked him, for all they had in common, there was such a large gap between her understanding of feelings and his. As scientifically rigorous as she tried to be, there were things about being human that she took for granted, that Ryuk had never experienced or perhaps even observed.

Sayu felt her temptations tugging her in several different directions, and she closed her eyes as she focused on naming and categorizing them. The first told her she wanted to push Ryuk away and never see him again, but that was an impossible desire to fulfill. The second wanted to ply him for all the knowledge she could get, try to stall or prevent Light's death sentence.

But would it be enough? Enough to put off just _one_ of the consequences of her brother's actions? Enough to keep him safe from the supernatural terror that now dwelt in her home, yet remain unable as always to shield him from the judgment of L, the police, and the world? Enough to stay the hand of the reaper, but not his own, as he plunged further into this madness, into his self-absorbed delusion? Would it be enough to truly be her brother's keeper?

No, Sayu knew, had always known, that it wouldn't. She regretted refusing to see how powerless her situation was until now. She rose, swinging her bare legs to dangle over the side of her bed.

Her third and final want was to make Ryuk understand, somehow, how his and Light's game was affecting her, and sort things out for herself if it turned out he just wasn't as invested in her friendship as he was in being entertained by Light's deranged ambitions. This seemed like the most realistic goal, given that she wasn't sure if saving him was even possible, and trying to ignore Ryuk for the rest of time would make her life difficult, and she would lose the one person she'd ever really gotten close to. And after all, weren't you supposed to be honest with friends?

(Not that she'd ever really obeyed that maxim with her human friends, but this was different situation, which required different tactics.)

A knock sounded at her door, and her mother's muffled voice came through. "Sayu, dinner's ready. I've made hotpot."

Sayu quickly wiped her tears away, checking her eyes in the mirror to make sure they weren't too red. "Isn't it way too early for hotpot? It's almost summer," she called out.

She heard her mother huff through the door. "Well you clearly haven't been outside, then, it's freezing." Her voice faded as she moved away from the door to the stairs.

"Okay, I'll be right down!" Sayu answered, slipping off the bed to stand. She checked herself in the mirror one last time, and headed downstairs.

The very next day, her father had a heart attack.

Her mother hadn't called the school, had waited for Sayu to come home, and told her about it then. Seeing her expression, Mom had hurried to put her arms on Sayu's shoulders and reassure her. "He's fine, Sayu, he's just fine! The doctor says its just stress – he's going to be on bed rest for a while in the hospital, but you can take the day off school tomorrow and come visit him. We didn't want to alarm you or pull you out of school today for no reason."

She had collapsed and sobbed into her mother's shoulder, clutching her sweater tightly. Mom had hugged her back, rocking her back and forth with soft assurances that everything was going to be all right.

If it wasn't one thing, it was another. In that instant, Sayu had truly dreaded the worst, that Light had truly murdered Dad, just because he was in the way or maybe just because he _could_ – but it was fine, Dad was fine, Light was fine, nothing was wrong.

Except for the fact that her father had just had a heart attack from the stress of trying to catch the mass-murdering serial killer living under his own roof. Somehow, that didn't exactly inspire optimism.

As Sayu sat at her desk, trying and failing to focus on her homework, a voice softly called out from one of the corners of her ceiling, "Sayu?"

She looked up, and there was Ryuk, warily peering down at her. "Is it okay to talk to you now?"

Sayu took a deep breath and leaned back in her chair, rolling it back as she did. "Yeah. Come on down."

He floated down, sitting crosslegged on top of her desk. "L and Light went to visit your dad in the hospital." There was no apology, nor did Sayu truly expect one. Ryuk probably wasn't even sure what he had done wrong.

"I didn't even hear Light come home. How did he react to the news?"

"...He was pretty shocked. The three of them had a discussion about Kira – L still thinks Light is a suspect, but your brother said he was willing to go under some kind of house arrest to prove his innocence."

"Sounds like he's got some dramatic scheme in mind. Did L take him up on it?"

"No, he says there's no need right now." Ryuk paused. "He seems to like playing mind games with Light, too. Light offered his own profile of Kira to try and throw L off the scent, and he picked out you as an example fitting that profile."

"L accused me?" Sayu was surprised more than anything else – given the detective's high opinion of her brother, she wasn't sure whether to take such a suspicion as flattering or insulting.

"I think he did it more to bother Light than anything else. It worked, too – Light flipped his lid at him for saying that in front of your dad in his condition. None of them actually think you'd be capable of it – your dad said if you had the power to kill like Kira, you'd probably have done it to someone you didn't like, and then cried about it."

Now _that_ stung, hearing that her father thought she was capable of doing such a thing, even if he thought she'd regret it. He'd probably meant it as a joke, but jokes meant a great deal more than the one telling them often thought. Did it make it better, or worse, knowing that he wasn't necessarily wrong, even if it wouldn't quite be the way he pictured it?

"What was the profile Light came up with?"

"Eh? Oh, he said it would have be an idealistic, purehearted wealthy child." Sayu snorted. "Yeah, I know, but neither of them argued that you weren't."

"Well, it just goes to show that they don't know me that well anymore." She stretched, and to avoid the sorrowful line of thinking she was about to go down, she added, "What does Light think of you disappearing now and then?"

Ryuk shrugged. "He thinks I just go around spying on you guys. I think he's glad to be rid of me sometimes – he enjoys having a witness around when he's got a plan, but when he's just writing names or doing ordinary stuff, he prefers privacy. I like that I don't have to tail him _that_ closely – I'd get pretty bored."

"I find it strange that he dismisses you so much, considering what you are. I would've thought he'd be more wary of your movements."

"He knows I'm not in this to interfere in any way."

"And he trusts that?"

Ryuk stood, looming over her. Sayu, completely enveloped in his shadow, started in surprise. "And you don't?"

She raised her gaze to meet his blood-red orbs. "I do. But I'm not so foolish as you think that you're incapable of taking action. You do meet with me without him knowing, don't you?"

For a moment, he was as still as stone. Then, he moved, sitting back down on the floor to be eye-level with her. "Kyeh-heh," he chuckled. "You've got a point."


End file.
